PARENT SESSION
SP3 - Trophic Transfer
Chair: Brown, Paige1, 1 U.S. Fish and Wildlife Service, VA
Co-chair: Foster, Gregory2, 2 George Mason University, Washington, DC
2:10 PM to 5:30 PM - Sunday, 17 November 2002
Room Ballroom H
(111) Persistent organochlorines in seabirds: relation to species, diet, condition and CYP 450 activity.
Borgå, Katrine*,1, Gabrielsen, Geir1, Wolkers, Hans1, Hop, Haakon1, Muir, Derek2, Skaare, Janneche3,4, 1 Norwegian Polar Institute, Tromsų, Norway2 National Water Research Institute, Burlington, Ontario, Canada3 Norwegian School of Veterinary Science, Oslo, Norway4 National Veterinary Institute, Oslo, Norway
ABSTRACT- Seabirds in the Barents Sea are not a uniform group with regard to organochlorine contaminant levels. Even among gulls and acids with comparable diets and hepatic contaminant concentrations, the hepatic contaminant patterns differ. Seabirds feeding mainly on copepods (the alcid little auk Alle alle), and fish, euphausiids and amphipods (the alcids Brunnichs guillemot Uria lomvia, black guillemot Cepphus grylle; the gull: black-legged kittiwake Rissa tridactyla) were collected in May 1999, along with their prey, in the Barents Sea marginal ice zone to study the reasons for the pattern and level differences in more details. The seabirds were analysed for hepatic organochlorine levels (PCBs and various pesticides), hepatic activity of CYP P450 enzymes (EROD and testosterone hydroxylase), and stable carbon and nitrogen isotope signals in muscle. Prey were analysed for PCBs, pesticides and stable isotopes to estimate the biomagnification to seabirds and the seabirds' metabolic index. Bioaccumulation of organochlorines is compound-structure dependent and related to exposure from the diet and the subsequent biotransformation within the organism, which can be reflected by looking into the CYP P450 enzyme activity in combination with the metabolic index. We attempted to separate the variation in organochlorine concentrations and patterns due to the species classification, nutritional status, sex, trophic position and cytochrome P450 enzyme activity.
Key words: trophic position, Arctic marginal ice zone, seabirds, CYP 450 isoenzyme activity